The current and long range plans of the Center require the services of and interaction with a Clinical Core facility focused on longitudinal study of patients with schizophrenia. The Core recruits and evaluates the following groups: never medicated first episode psychotic patients; medication free later episode schizophrenic patients; normal subjects for comparison with first episode schizophrenic patients (a subset of the first episode psychotic patients) and normal subjects for comparison with later episode schizophrenic subjects. All subjects are evaluated with a Core Assessment Battery that includes structured diagnostic interviews, longitudinal diagnostic reviews, detailed assessment of clinical psychopathology, neurological dysfunction and other measures to insure common, uniform evaluations. Data from the Core Assessment Battery are provided to all investigators who study these patients. To support the longitudinal study design utilized with first episode patients, the Clinical core provides clinical follow-up for many of them. Within the Center, David Lewis, M.D. (Project 2) and James L. McClelland, Ph.D. (Project 7) present specific plans to utilize Core resources. Seven other NIMH funded collaborating investigators also utilize Core resources. The presence of a carefully defined clinical population stimulates close collaboration of clinical and basic researchers by providing a mechanism for the direct testing of basic concepts in the clinic. In addition, the Core enlarges the net of collaborating projects that are only cost effective if the costs of recruitment and assessment are shared. Much prior research on the neurobiological substrate of schizophrenia has faltered because of an inability to disentangle primary characteristics from those that emerge as part of the course of the disorder. Only prospective study such as that proposed here can hope to identify basic neurobiological flaws that may lead to successful treatment and ultimately to prevention of schizophrenia.